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US5053438A - Foam material - Google Patents

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Publication number
US5053438A
US5053438A US07/479,601 US47960190A US5053438A US 5053438 A US5053438 A US 5053438A US 47960190 A US47960190 A US 47960190A US 5053438 A US5053438 A US 5053438A
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United States
Prior art keywords
foam material
density polyethylene
resin
polyethylene
low density
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/479,601
Inventor
Matthew L. Kozma
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Packaging Industries Group Inc
Original Assignee
Packaging Industries Group Inc
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Filing date
Publication date
Priority claimed from US07/361,761 external-priority patent/US4900490A/en
Application filed by Packaging Industries Group Inc filed Critical Packaging Industries Group Inc
Priority to US07/479,601 priority Critical patent/US5053438A/en
Application granted granted Critical
Publication of US5053438A publication Critical patent/US5053438A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/10—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
    • C08J9/102—Azo-compounds
    • C08J9/103—Azodicarbonamide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/05—Use of one or more blowing agents together

Definitions

  • the invention relates to foam material particularly useful for midsole material used in athletic shoes.
  • EVA Ethylene vinyl acetate
  • a heel wedge may be incorporated into the midsole.
  • ethylene propylene diene monomer used alone
  • styrene-butadiene rubber used alone
  • neoprene used alone
  • a new improved foam midsole material comprises polyethylene modified by an elastomer.
  • a preferred elastomer for use as a modifier is ethylene propylene diene monomer (EPDM).
  • EPDM ethylene propylene diene monomer
  • the elastomer is used as a modifier for a polyethylene material comprising at least one member selected from, for example, low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
  • Use of an elastomer modified polyethylene enhances the properties of a midsole molded from such material.
  • the material may also be used for molding an outer sole.
  • An object of the invention is to provide a novel foam material.
  • Another object of the invention is to provide a novel foam material for use as a midsole material for an athletic shoe.
  • Yet another object of the invention is to provide a novel foam material for use as an outer sole material for an athletic shoe.
  • Shoe sole material must have good rebound qualities and high tensile strength.
  • the midsole is the working part of the shoe and must be shock resistant to provide comfort since the midsole absorbs the impact of use.
  • the outer sole is generally molded to include traction elements and the material used must be abrasion resistant to provide good wearing qualities.
  • the inner sole of an athletic shoe provides foot comfort.
  • the foam material of the invention may be used either for the midsole or for the outer sole or for both the midsole and the outer sole.
  • the soles may be produced by compression molding or by injection molding or the foam material may be formed into a sheet and then cut to shape Other methods will be apparent to one skilled in the art.
  • a foam material of the invention for use, for example, in soling compound for athletic shoes comprises polyethylene modified by an elastomer.
  • Use of an elastomer to modify polyethylene used in midsole material for athletic shoes enhances the properties of the midsole, particularly providing improved energy return and reduced sensitivity to temperature change compared with prior art materials such as elastomer used alone or EVA.
  • the foam material comprises polyethylene modified by an elastomer and cross-linked to form a closed cell foam material.
  • the elastomer modifier is preferably ethylene propylene diene monomer (EPDM) and the polyethylene is, for example, at least one member selected from the group consisting of low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
  • Cross-linking may be carried out in a number of known ways, for example, using peroxide, radiation curing, silane cross-linking, or other known methods. Peroxide cross-linking is the preferred method.
  • the following example demonstrates an advantageous material of the invention providing improved energy return, resistance to compression set and resistance to abrasion, and reduced sensitivity of performance characteristics to temperature change than elastomer alone, EVA or other prior art compounds.
  • the blowing agent (KEMPORE 60/14 ff) is azodicarbonamide, the cross-linking agent (LUPERCO 500 - 40 KE) is dicumyl peroxide.
  • examples of other compounds useful in the invention include:
  • EPDM styrene-butadiene rubber
  • SBR styrene-butadiene rubber
  • neoprene nitrile
  • acrylic etc.
  • Polyethylene low density polyethylene (LDPE), linear LDPE, ultra LDPE, high density polyethylene, etc.
  • Blowing agent azodicarbonamide, dinitroso-pentamethylene tetramine (DNPT), 4, 4' oxybis (benzenesulfonyl) hydrazine (OBSH), etc.
  • Activator Zinc stearate, zinc oxide, etc.
  • Cross-linking agent dicumyl peroxide, di-tertiarybutyl peroxide, silane, methacrylate coupling agents, etc.
  • Pigments and fillers may optionally be included. Extenders, such as oils or plasticizers may also be used.
  • a typical production process for manufacturing a material of Example 1 of the invention comprises fusion mixing EPDM and low density polyethylene (LDPE) in a dispersion mixer for 15-20 minutes at 320° F., and then sheeting or pelletizing and cooling the material to about 280° F.
  • the remaining ingredients, shown in Example 1 are added (in the stated proportions) to the EPDM/LDPE fused mixture, mixed in a dispersion mixer at about 280° F., and passed through a roll mill for sheeting.
  • the sheets are cooled, cut, and press molded in a hydraulic press for 30 minutes at 340° F. to produce a midsole pad which is then cured and expanded as known in the art.
  • Test samples were cured for thirty minutes at 340° F. (without oven normalization), molded in a 6 in. ⁇ 6 in. ⁇ 1/2 in. mold, and tested. Results showed that, with a density lower than ethylene vinyl acetate (EVA), energy return properties are better than EVA, and the material has 25% less sensitivity to changes in temperature than EVA.
  • EVA ethylene vinyl acetate
  • the density of the material is about 7 to 10 lb./cu. ft. Tear resistance is about 18 to 22 lb./in.
  • the combination of properties which determine improved energy return and reduced sensitivity of energy return to temperature change are dependent on the tensile strength and elongation of the material. Increased tensile strength is balanced against reduction in elongation in determining the optimum combination providing improved energy return.
  • the density of the material may be varied according to the amount of blowing agent used.
  • the blowing agent may be incorporated with the polyethylene and such a formulation (for example, NORTECK 1150) may be used in place of at least part of the LDPE and/or blowing agent used in the formulation of the foam.
  • NORTECK 1150 a formulation
  • the LDPE (NORCHEM) fused with the EPDM (NORDEL) may constitute only part of the total LPPE.
  • Other examples of formulations of the invention are as follows:
  • Table I shows test results for cross-linked foams of Example 1 of the invention.
  • Specimens A, B and C differ only by the LDPE used.
  • Specimen A is NORCHEM 953
  • specimen B is NORCHEM 963
  • specimen C is NORCHEM 553.
  • Other similar formulations will be apparent to one skilled in the art.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Abstract

A foam material, particularly suitable for use as a midsole material for an athletic shoe, comprises polyethylene modified by an elastomer modifier and cross-linked, preferably using a peroxide cross-linking agent, to form a closed cell foam material which has superior strength properties, improved energy return and reduced sensitivity to temperature change.

Description

RELATED APPLICATIONS
This application is a continuation of Ser. No. 361,761, filed June 5, 1989, now U.S. Pat. No. 4,900,490, which is a continuation of Ser. No. 051,141 filed May 15, 1987, abandoned.
FIELD OF THE INVENTION
The invention relates to foam material particularly useful for midsole material used in athletic shoes.
BACKGROUND OF THE INVENTION
Athletic shoes have an outer sole designed to maintain traction and a midsole to both cushion the foot and control the gait. Midsole material must be carefully formulated since cushioning often comes at the expense of control, and vice-versa. A midsole engineered to control motion may often include two or three different densities of foam material. Ethylene vinyl acetate (EVA) and/or the more expensive polyurethane are often used, and may be used in the same midsole, with the firmer, heavier densities concentrated in the areas bearing the greatest impact (the heel, inner side of the mid-foot, and under the ball of the foot). A heel wedge may be incorporated into the midsole.
Other materials previously used for midsole material of athletic shoes include ethylene propylene diene monomer (used alone), styrene-butadiene rubber and neoprene.
SUMMARY OF THE INVENTION
A new improved foam midsole material comprises polyethylene modified by an elastomer. A preferred elastomer for use as a modifier is ethylene propylene diene monomer (EPDM). The elastomer is used as a modifier for a polyethylene material comprising at least one member selected from, for example, low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene. Use of an elastomer modified polyethylene enhances the properties of a midsole molded from such material. The material may also be used for molding an outer sole.
An object of the invention is to provide a novel foam material.
Another object of the invention is to provide a novel foam material for use as a midsole material for an athletic shoe.
Yet another object of the invention is to provide a novel foam material for use as an outer sole material for an athletic shoe.
DETAILED DESCRIPTION OF THE INVENTION
Shoe sole material must have good rebound qualities and high tensile strength. The midsole is the working part of the shoe and must be shock resistant to provide comfort since the midsole absorbs the impact of use. The outer sole is generally molded to include traction elements and the material used must be abrasion resistant to provide good wearing qualities. The inner sole of an athletic shoe provides foot comfort.
The foam material of the invention may be used either for the midsole or for the outer sole or for both the midsole and the outer sole. The soles may be produced by compression molding or by injection molding or the foam material may be formed into a sheet and then cut to shape Other methods will be apparent to one skilled in the art.
A foam material of the invention for use, for example, in soling compound for athletic shoes comprises polyethylene modified by an elastomer. Use of an elastomer to modify polyethylene used in midsole material for athletic shoes enhances the properties of the midsole, particularly providing improved energy return and reduced sensitivity to temperature change compared with prior art materials such as elastomer used alone or EVA.
The foam material comprises polyethylene modified by an elastomer and cross-linked to form a closed cell foam material. The elastomer modifier is preferably ethylene propylene diene monomer (EPDM) and the polyethylene is, for example, at least one member selected from the group consisting of low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
Cross-linking may be carried out in a number of known ways, for example, using peroxide, radiation curing, silane cross-linking, or other known methods. Peroxide cross-linking is the preferred method.
The following example demonstrates an advantageous material of the invention providing improved energy return, resistance to compression set and resistance to abrasion, and reduced sensitivity of performance characteristics to temperature change than elastomer alone, EVA or other prior art compounds.
EXAMPLE 1
The following formulation was used to provide a foam material of the invention:
______________________________________                                    
                    Parts per Hundred                                     
______________________________________                                    
EPDM (NORDEL No. 1440)                                                    
                      100.0                                               
Low density polyethylene                                                  
                      100.0                                               
(NORCHEM LDPE 553)                                                        
Blowing agent (KEMPORE 60/14 ff)                                          
                      10.0                                                
Activator (zinc stearate)                                                 
                      5.0                                                 
Cross-linking agent (LUPERCO                                              
                      4.0                                                 
500 - 40 KE)                                                              
______________________________________
The blowing agent (KEMPORE 60/14 ff) is azodicarbonamide, the cross-linking agent (LUPERCO 500 - 40 KE) is dicumyl peroxide. Examples of other compounds useful in the invention include:
Elastomer EPDM, styrene-butadiene rubber (SBR), neoprene, nitrile, acrylic, etc.
Polyethylene: low density polyethylene (LDPE), linear LDPE, ultra LDPE, high density polyethylene, etc.
Blowing agent: azodicarbonamide, dinitroso-pentamethylene tetramine (DNPT), 4, 4' oxybis (benzenesulfonyl) hydrazine (OBSH), etc.
Activator: Zinc stearate, zinc oxide, etc.
Cross-linking agent: dicumyl peroxide, di-tertiarybutyl peroxide, silane, methacrylate coupling agents, etc.
Pigments and fillers may optionally be included. Extenders, such as oils or plasticizers may also be used.
A typical production process for manufacturing a material of Example 1 of the invention comprises fusion mixing EPDM and low density polyethylene (LDPE) in a dispersion mixer for 15-20 minutes at 320° F., and then sheeting or pelletizing and cooling the material to about 280° F. The remaining ingredients, shown in Example 1, are added (in the stated proportions) to the EPDM/LDPE fused mixture, mixed in a dispersion mixer at about 280° F., and passed through a roll mill for sheeting. The sheets are cooled, cut, and press molded in a hydraulic press for 30 minutes at 340° F. to produce a midsole pad which is then cured and expanded as known in the art.
Test samples were cured for thirty minutes at 340° F. (without oven normalization), molded in a 6 in.×6 in.×1/2 in. mold, and tested. Results showed that, with a density lower than ethylene vinyl acetate (EVA), energy return properties are better than EVA, and the material has 25% less sensitivity to changes in temperature than EVA. The density of the material is about 7 to 10 lb./cu. ft. Tear resistance is about 18 to 22 lb./in.
The combination of properties which determine improved energy return and reduced sensitivity of energy return to temperature change are dependent on the tensile strength and elongation of the material. Increased tensile strength is balanced against reduction in elongation in determining the optimum combination providing improved energy return. The density of the material may be varied according to the amount of blowing agent used.
In alternative formulations, the blowing agent may be incorporated with the polyethylene and such a formulation (for example, NORTECK 1150) may be used in place of at least part of the LDPE and/or blowing agent used in the formulation of the foam. Moreover, the LDPE (NORCHEM) fused with the EPDM (NORDEL) may constitute only part of the total LPPE. Other examples of formulations of the invention are as follows:
______________________________________                                    
             Example                                                      
             1    2      3      4    5    6                               
______________________________________                                    
*EPDM (NORDEL 1440)                                                       
               100    100    100  100  100  100                           
*LDPE (NORCHEM 553)                                                       
               100    100    100  25   100  100                           
LDPE (NORCHEM 553)                                                        
               --     100    25   --   60   --                            
Blowing agent  10     15     --   --   15   --                            
(KEMPORE 60/14 ff)                                                        
Zinc stearate  5      7.5    7.5  5    6.5  6.5                           
LUPERCO 500 40 KE                                                         
               4      6      6    4    5.2  5.2                           
NORTECK 1150   --     --     75   75   --   75                            
(20% blowing agent)                                                       
______________________________________                                    
 *fused for 30 minutes at 340° F.
Table I shows test results for cross-linked foams of Example 1 of the invention. Specimens A, B and C differ only by the LDPE used. Specimen A is NORCHEM 953, specimen B is NORCHEM 963 and specimen C is NORCHEM 553. Other similar formulations will be apparent to one skilled in the art.
Comparative results with EPDM used alone, in a prior art formulation are as follows:
______________________________________                                    
                Parts Per Hundred                                         
______________________________________                                    
EPDM (ROYALENE 521)                                                       
                  80.0                                                    
EPDM (ROYALENE 512)                                                       
                  20.0                                                    
Stearic Acid      2.0                                                     
Zinc Oxide        5.0                                                     
Carbowax 4000     3.0                                                     
N672, SRF Black   15.0                                                    
Suprex Clay       175.0                                                   
Sunpar 150        55.0                                                    
BIK-OT ®      2.0                                                     
CELOGEN ® AZ 130                                                      
                  8.0                                                     
MBTS ®        .5                                                      
Sulfur            2.0                                                     
                  367.5                                                   
______________________________________                                    

                                  TABLE I                                 
__________________________________________________________________________
TEST RESULTS: CROSS-LINKED FOAM                                           
__________________________________________________________________________
DENSITY:                                                                  
SPECIMEN WEIGHT (grams)                                                   
                       SAMPLE SIZE (in.)                                  
                                  DENSITY (lbs./ft..sup.3)                
__________________________________________________________________________
A        4.59          .551 × 2.003 × 2.026                   
                                  7.82                                    
B        4.48          .526 × 1.988 × 2.018                   
                                  8.09                                    
C        4.93          .513 × 1.993 × 2.019                   
                                  9.10                                    
__________________________________________________________________________
COMPRESSION DEFLECTION: (Crosshead 2 in./min.)                            
                              COMPRESSION DEFLECTION                      
SPECIMEN ACTUAL SIZE (in.)                                                
                       LOAD (lbs.)                                        
                              lbs./in..sup.2 @ 25% DEF.                   
__________________________________________________________________________
A1       .551 × 2.003 × 2.026                                 
                       110              27.1                              
A2       .551 × 1.995 × 2.029                                 
                       118              29.2                              
A3       .536 × 2.021 × 2.012                                 
                       114              28.0                              
                              AVG.      28.1                              
B1       .526 × 1.988 × 2.018                                 
                       114              28.4                              
B2       .526 × 1.989 × 2.011                                 
                       116              29.0                              
B3       .536 × 1.978 × 2.016                                 
                       122              30.6                              
                              AVG.      29.3                              
C1       .531 × 1.993 × 2.019                                 
                        89              22.1                              
C2       .505 × 2.028 × 1.979                                 
                        84              20.9                              
C3       .502 × 2.026 ×  1.969                                
                        84              21.1                              
                              AVG.      21.4                              
__________________________________________________________________________
TEAR RESISTANCE: (Crosshead 20 in./min.)                                  
SPECIMEN  THICKNESS (in.)  LOAD (lbs.)                                    
                                  TEAR (lbs./in.)                         
__________________________________________________________________________
A1        .487             10.4           21.4                            
A2        .482             10.0           20.7                            
A3        .495             10.0           20.2                            
                                  AVG.    20.8                            
B1        .496             10.4           21.0                            
B2        .501             10.0           20.0                            
B3        .485              8.4           17.3                            
                                  AVG.    19.4                            
C1        .497             11.1           22.3                            
C2        .492              9.0           18.3                            
C3        .507             10.3           20.3                            
                                  AVG.    20.3                            
__________________________________________________________________________
TENSILE STRENGTH AND ELONGATION: (Crosshead 20 in./min.)                  
       WIDTH                                                              
            THICKNESS                                                     
                    ULT.   TENSILE STRENGTH                               
SPECIMEN                                                                  
       (in.)                                                              
            (in.)   LOAD (lbs.)                                           
                           (lbs./in..sup.2)                               
                                       % ELONGATION                       
__________________________________________________________________________
A1     .460 .493    42           185   175                                
A2     .465 .529    40           163   144                                
A3     .460 .518    44           185   150                                
                           AVG.  178   156                                
B1     .463 .531    46           187   188                                
B2     .460 .495    41           180   175                                
B3     .463 .523    43           178   150                                
                           AVG.  182   171                                
C1     .467 .487    40           176   150                                
C2     .464 .495    40           174   150                                
C3     .465 .486    41           181   138                                
                           AVG.  177   146                                
__________________________________________________________________________
COMPRESSION SET: 50% Def. for 22 hrs.   24 hrs. Recovery   Values are %   
of Original Thickness                                                     
        ORIGINAL   ACTUAL % DEF.                                          
                              THICKNESS AFTER                             
SPECIMEN                                                                  
        THICKNESS (in.)                                                   
                   W/.25" STOPS                                           
                              RECOVERY (in.)                              
                                           % SET                          
__________________________________________________________________________
A1      .551       45.8       .517         6.2                            
A2      .542       46.1       .507         6.5                            
A3      .542       46.1       .500         7.7                            
B1      .541       46.2       .507         6.3                            
B2      .537       46.6       .506         5.8                            
B3      .534       46.8       .502         6.0                            
C1      .514       48.6       .485         5.6                            
C2      .517       48.4       .485         6.2                            
C3      .515       48.5       .486         5.6                            
__________________________________________________________________________
Curing conditions: press molded for 20 minutes at 320° F. for 3/4" thickness and oven aged for 3 hours at 250° F. Test results for this product are as follows:
______________________________________                                    
ML-4 at 212° F.  34                                                
Expanded Density, lbs./cu. ft.                                            
                        12.5                                              
Tensile strength (lbs./sq. in.)                                           
                        100                                               
Elongation, %           280                                               
Water absorption, vacuum method, %                                        
                        1.5                                               
25% Compression Deflection, (lbs./sq. in.)                                
                        6.0                                               
______________________________________
Comparing the properties of the compounds of Table I with the properties of EPDM alone (shown above), it is clear that the inventive compounds have substantially improved compression deflection and tensile strength and substantially reduced elongation when compared with EPDM used alone.
While the invention has been described above with respect to certain embodiments thereof, it will be appreciated that variations and modifications may be made without departing from the spirit and scope of the invention.

Claims (8)

What is claimed is:
1. A foam material made by a process comprising:
fusing a resin mixture comprising ethylene-propylene diene terpolymer, polyethylene and a chemically decomposing blowing agent in a dispersion mixer;
sheeting the fused resin;
cooling the sheet resin;
press molding the sheet resin in a hydraulic press;
curing the resin during the press molding step, and
expanding the cured molded resin immediately on opening the press to form a foam material having a density of about 7 to 10 lb. cu. ft. and a tear resistance of about 18 to 22 lb./in.
2. A foam material according to claim 1 wherein the fusing step comprises fusing crosslinking agent with the resin.
3. A foam material according to claim 1 wherein said polyethylene comprises at least one member selected from the group consisting of low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
4. A thermosetting foam material made by a process comprising:
fusing a resin mixture comprising ethylene-propylene diene terpolymer, polyethylene and a chemically decomposing blowing agent in a dispersion mixer;
sheeting the fused resin;
cooling the sheet resin;
press molding the sheet resin in a hydraulic press;
curing the resin during the press molding step, and
expanding the cured molded resin immediately on opening the press to form a foam material having a density of about 7 to 10 lb. cu. ft., a tear resistance of about 18 to 22 lb./in., a compression deflection at 25% deflection greater than 20 lb./sq. in., a tensile strength greater than 175 lb./sq. in. and an elongation greater than 150%, proving improved energy return and reduced sensitivity of energy return to temperature change compared with elastomer alone.
5. A foam material according to claim 4 wherein said polyethylene comprises at least one member selected from the group consisting of low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
6. A thermosetting, closed cell crosslinked foam material comprising a fused mixture of ethylene-propylene diene terpolymer and polyethylene, wherein the foam material has a compression deflection at 25% greater than 20 lb./sq. in., a tensile strength greater than 175 lb./sq. in. and an elongation greater than 150%, providing improved energy return and reduced sensitivity of energy return to temperature change compared with elastomer alone.
7. A foam material according to claim 6 wherein the foam material has a density of about 7 to 10 lb./cu. ft. and a tear resistance of about 18 to 22 lb./in.
8. A foam material according to claim 6 wherein said polyethylene comprises at least one member selected from the group consisting of low density polyethylene, linear low density polyethylene, ultra low density polyethylene and high density polyethylene.
US07/479,601 1987-05-15 1990-02-13 Foam material Expired - Fee Related US5053438A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US07/479,601 US5053438A (en) 1987-05-15 1990-02-13 Foam material

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US5114187A 1987-05-15 1987-05-15
US07/361,761 US4900490A (en) 1987-05-15 1989-06-05 Foam material
US07/479,601 US5053438A (en) 1987-05-15 1990-02-13 Foam material

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US07/361,761 Continuation US4900490A (en) 1987-05-15 1989-06-05 Foam material

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5137933A (en) * 1991-03-04 1992-08-11 Ube Cycon, Ltd. Foamable resin composition
US5385980A (en) * 1992-06-11 1995-01-31 Zeon Chemicals U.S.A., Inc. Curable halobutyl rubber/poly-epihalohydrin rubber blends
US5554694A (en) * 1990-12-21 1996-09-10 Crow; William R. Performance enhancing athletic shoe components and methods
US5695850A (en) * 1993-01-29 1997-12-09 Crow; William R. Performance enhancing athletic shoe components and methods
US6096793A (en) * 1998-12-22 2000-08-01 Sealed Air Corporation Foam comprising polyolefin blend and method for producing same
US6120880A (en) * 1995-03-23 2000-09-19 Crow; William R. Performance enhancing athletic shoe components and methods
US6492013B1 (en) 2001-03-28 2002-12-10 Sealed Air Corporation Foam composite structure comprising a blend of polypropylene and homogeneous ethylene/alpha-olefin copolymer
US6589630B1 (en) 1995-03-23 2003-07-08 William R. Crow Performance enhancing shoe components and methods
US6809125B1 (en) 2000-06-02 2004-10-26 Sealed Air Corporation (Us) Foam comprising polyolefin blend and method for producing same
US20050065270A1 (en) * 2000-03-02 2005-03-24 Adidas International B.V. Polymer composition
US20080066342A1 (en) * 2004-11-12 2008-03-20 Park Jang W Shock-Absorbing Device for Shoes

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US3709806A (en) * 1970-06-27 1973-01-09 Toray Industries Process for the preparation of radiation-crosslinkable foamable polyolefin particles
US3965054A (en) * 1973-04-10 1976-06-22 The Furukawa Electric Co., Ltd. Foamable polyolefin composition and method for manufacturing foamed polyolefin
US4212787A (en) * 1977-05-26 1980-07-15 Mitsui Petrochemical Industries Ltd. Thermoplastic elastomer composition, blends of the composition with olefin plastic, and foamed products of the composition and the blends
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US4446254A (en) * 1980-02-21 1984-05-01 The Furukawa Electric Co., Ltd. Crosslinked polyolefin foam containing a high concentration of an inorganic material and process for producing the same
US4680317A (en) * 1981-08-17 1987-07-14 Dynamit Nobel Aktiengesellschaft Molding composition for crosslinked foam material from polyolefins and ethylene-propylene elastomer, and process for the production of the foam material
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US4738810A (en) * 1984-07-04 1988-04-19 The Dow Chemical Company Foams of linear low density polyethylene and a method for their preparation
US4719039A (en) * 1985-01-02 1988-01-12 Dynamit Nobel Of America, Inc. Electrically conductive polyethylene foam
US4581383A (en) * 1985-04-19 1986-04-08 The Dow Chemical Company Lightly crosslinked linear olefinic polymer foam blends and process for making
US5510031A (en) * 1994-09-13 1996-04-23 Ametek, Inc. Faucet assembly with replaceable filter

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5554694A (en) * 1990-12-21 1996-09-10 Crow; William R. Performance enhancing athletic shoe components and methods
US5137933A (en) * 1991-03-04 1992-08-11 Ube Cycon, Ltd. Foamable resin composition
US5385980A (en) * 1992-06-11 1995-01-31 Zeon Chemicals U.S.A., Inc. Curable halobutyl rubber/poly-epihalohydrin rubber blends
US5695850A (en) * 1993-01-29 1997-12-09 Crow; William R. Performance enhancing athletic shoe components and methods
US6120880A (en) * 1995-03-23 2000-09-19 Crow; William R. Performance enhancing athletic shoe components and methods
US6589630B1 (en) 1995-03-23 2003-07-08 William R. Crow Performance enhancing shoe components and methods
US6096793A (en) * 1998-12-22 2000-08-01 Sealed Air Corporation Foam comprising polyolefin blend and method for producing same
US20050065270A1 (en) * 2000-03-02 2005-03-24 Adidas International B.V. Polymer composition
US6809125B1 (en) 2000-06-02 2004-10-26 Sealed Air Corporation (Us) Foam comprising polyolefin blend and method for producing same
US6492013B1 (en) 2001-03-28 2002-12-10 Sealed Air Corporation Foam composite structure comprising a blend of polypropylene and homogeneous ethylene/alpha-olefin copolymer
US20080066342A1 (en) * 2004-11-12 2008-03-20 Park Jang W Shock-Absorbing Device for Shoes

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